If catalytic reduction of 4-tosyloxy-5, 6, 7, 8-tetrahydroisoquinoline (IV) could effect detosyloxylation to form the 5, 6, 7, 8-tetrahydroisoquinoline (V), it would be a new method for preparing (V) from coal-tar isoquinoline. (IV) was therefore prepared but it resisted to reduction under conditions similar to those in the case of 4-tosyloxyisoquinoline. Examination of catalyst and additives showed that the catalytic reduction could be effected by using the catalyst which was prepared by preliminary treatment of Adams' platinum oxide with hydrogen followed by addition of platinum chloride and shaking in hydrogen stream, all in ethanolic solution. By this means, (V) was obtained in a good yield.
